Bio Ch17 – History of Life on Earth How long has life been on Earth? What are the relationships between organisms as time moved forward? 1

Fossil Records 2

3 Petrified tree sap = amber (Basis for Jurassic Park movies)

Fossil Evidence In 2004, scientists digging in the Canadian Arctic unearthed fossils of a half-fish, half- amphibian that all but confirmed paleontologists' theories about how land- dwelling tetrapods–four-limbed animals, including us–evolved from fish. It is a classic example of a transitional form, one that bridges a so-called evolutionary gap between different types of animal. Lets examine five important cases. 4

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Fossil Formation Lucy 10

Age-determining Techniques Biological – tree rings Geologic – sedimentary layers Geochemical – Sea salt concentration Geophysical – Relative cooling of earths crust Chemical – Weathering Relative dating – Fossil relations Radioactive dating – Comparative amount of elements 11

Relative Dating 12

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Radioactive dating 14

Radioactive decay in everyday life 15

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Geologic Time Scale Evidence used to construct timeline of development of life on Earth Fossil records Relative Dating Radioactive dating LEADS TO 17

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Early Earth Atmosphere Hydrogen Cyanide Carbon Dioxide Carbon Monoxide Nitrogen Hydrogen Sulfide Water 20

Patterns of Evolution (Macroevolution) Extinction Adaptive Radiation Convergent Evolution Coevolution Punctuated Equilibrium Changes in developmental genes 21

Extinction Mass extinctions –Causes –Impact on life 22

Adaptive Radiation 23

Convergent Evolution Similar torpedo-shape body & fluke/tail. Mammals were initially land-based with four walking limbs. 24

Coevolution Evolution of separate species in response to each other (not abiotic response) 25

Punctuated Equilibrium 26

Changes in Developmental Genes Genetic change can produce major evolutionary transformation 27